\\[-1.8ex] Soil Heterogeneity & $-$0.108$^{*}$ & $-$0.106 & $-$0.115$^{**}$ & $-$0.081$^{***}$ & $-$0.077$^{***}$ & $-$0.094$^{***}$ \\ 
  & (0.065) & (0.066) & (0.049) & (0.030) & (0.030) & (0.029) \\ 
\\[-1.8ex] 
Observations & 23,431 & 23,431 & 23,431 & 23,431 & 23,431 & 23,369 \\ 
R$^{2}$ & 0.003 & 0.028 & 0.309 & 0.577 & 0.599 & 0.611 \\ 
